Marking cartridges are designed to propel a non-lethal marking projectile to a target and deposit a visual indicator at the impact point of the projectile. Typically, the marking projectile is mounted to a specialized cartridge casing which launches the marking projectile at a non-lethal velocity to the target. Currently, many of the specialized cartridge casings attempt to mimic cartridge casings used for conventional ammunition such that the marking cartridge can be fired from conventional firearms with minimal or no modifications to the firearm.
The marking media deposited on impact typically comprises colored powder, liquid, paste or gel. The marking media is often encased in a frangible shell that fractures on impact which reduces the impact force of the projectile and releases the marking material. While the frangible shell needs to effectively convey the marking media to the impact point, it also needs to survive the mechanical engagements associated with cartridge handling and loading in conventional firearms. The frangible shell can become cracked or shatter during the loading process depositing the marking media and/or shell material within the firearm or otherwise rendering the marking projectile unsuitable for firing. During firing, the frangible shell is brittle and may not optimally engage the rifling of the barrel or may be damaged by such engagement. With less than optimal engagement of the rifling, a marking projectile cannot properly simulate a conventional projectile, which is rotated rapidly along its axial axis by the rifling to increase the accuracy of the bullet. The lightweight materials commonly used in marking projectiles exacerbate the problem by increasing the effect of environmental factors, for example wind, on the flight path of the marking projectile. A lack of adequate axial rotation and the light weight of the projectile can result in a dramatic decrease in accuracy.
Moreover, the marking media itself may decrease the accuracy or otherwise impact the flight of the marking projectile. As the marking media typically comprises liquids or powder, any inconsistencies in the packing of the marking media, such as air bubbles or an uneven distribution of marking media, can cause the marking media to shift during flight preventing the projectile from flying straight or cause the projectile to cork screw in flight. The discrete size of the marking projectile makes evenly and precisely loading the marking media into the marking projectile more difficult, which increases the likelihood that there will be manufacturing inconsistencies and quality control issues. A marking projectile is needed that provides more optimal engagement of the barrel rifling, has improved accuracy, has suitable strength for firing, and is suitably frangible on impact.
Furthermore, maintaining the non-solid marking material within the projectile can be difficult when the projectile is subjected to varying ambient conditions during long storage periods. Paste and liquid marking fluids are known to leak from stored conventional marking cartridges which can render the cartridges useless or present a hazard and other difficulties when the cartridge is attempted to be used in a firearm. A marking projectile is needed with greater marking fluid containment integrity and greater uniformity in the packing of the marking fluid in the projectile.
The relative weight difference between marking projectiles and conventional cartridges can also impact operation of the firearm. As marking projectiles are typically substantially lower in weight than conventional bullets, less propellant is required to propel a marking projectile as compared to a conventional bullet. The reduced propellant load also reduces the blowback of the casing when the marking projectile is fired. The reduced blowback may be insufficient to operate the ejector mechanism of a conventional firearm and eject the spent casing from the firearm. The inability of marking projectiles to properly operate the ejection and reloading mechanisms of conventional firearms may force users to manually chamber a new round after each marking projectile is fired and prevent marking projectiles from being effectively used in automatic and semi-automatic firearms. Marking cartridges are needed that provides the desirable attributes above and which may reliably be used in conventional firearms.